In the mobile communication system, in order to meet the requirement of mobility, after User Equipment (UE) establishes a connection with a network in a certain cell, the UE still needs to measure the signal quality of the serving cell and the neighbour cell, so as to select an appropriate cell for handover. Taking EUTRAN (Evolved Universal Terrestrial Radio Access Network) as an example, the specific process of the measurement performed by the UE in the connection state is: the network side transmits a measurement control message to the UE, wherein the measurement control message comprises Measurement Identity (MID), event type, measurement object, and attributes that need to be measured; the UE performs parameter initialization according to the measurement identity in the measurement control message, and acquires the attributes and measurement result of each measurement object among all the measurement objects in the measurement control message; the UE performs event evaluation for the measurement result of each measurement object according to the initialized parameters or a predetermined offset (offset) value, and determines, through the evaluation, the measurement objects that meet the trigger conditions of the measurement events and have a duration greater than or equal to a Time To Trigger (TTT) among all the measurement objects; the UE places these measurement objects (at this time, the measurement objects have already been corresponded to cells) which meet a event trigger condition, into a cell list (cellsTriggeredList) of the measurement identity corresponding to the event; and the UE generates a measurement report according to the measurement results of the determined measurement objects, and transmits the measurement report to the network side, the measurement objects contained in the measurement report are all acquired from the cell list of the measurement identity corresponding to the event.
In the mobile communication system, frequency or a cell set at the frequency forms the unit of the measurement object, and the measurement configuration consists of measurement assignments. Each measurement assignment comprises one measurement identity, one measurement object and one reporting configuration (e.g., event triggering or periodical report). Herein the measurement identity indicates the corresponding measurement object and the corresponding reporting configuration. In the LTE (Long Term Evolution) system, one measurement object corresponds to one frequency, and the reporting configuration can define event report and periodic report which specifically comprise event report type or periodical report type and the corresponding parameters, for example, an event typically comprises event trigger condition, exit condition, event specific offset (Thresh), event hysteresis parameter (Hys), duration of event trigger condition, event offset (Offset) and so on.
In order to meet the mobility requirements of the UE under the connection state, it is required that the UE measures the serving cell and the neighbour cell and reports the measurement objects meeting the event trigger condition. At present, some measurement events for the serving cell have been defined, for example, defining the trigger condition for the measurement event as the signal quality of the serving cell being higher than a predetermined offset (A1 event), or as the signal quality of the serving cell being lower than a predetermined offset (A2 event); as to the measurement event of the neighbour cell, for example, defining the trigger condition of the measurement event as the signal quality of the neighbour cell being higher than a certain offset (A4 event), or as the signal quality of the neighbour cell being higher than the signal quality of the current serving cell by a predetermined offset (A3 event).
To measure the measurement object, different systems use different measurement methods, which all reflect signal quality of the cell. In the LTE, what the UE measures is Reference Signal Received Power (RSRP, the unit thereof is dBm) or Reference Signal Received Quality (RSRQ, the unit thereof is dB). In the WCDMA, what the UE measures is Received Signal Code Power (RSCP, the unit thereof is dBm) of the common pilot channel or Ec/No (indicating the ratio of the energy of each chip on each code channel after the transmitter spreading the spectrum versus the power spectral density of the band limited white noise) of the common pilot channel, which takes dB as the unit. When comparing the signal qualities of different cells, the UE needs to compare the measurement results of the same type. When evaluating the measurement object meets the event trigger condition (taking the A3 event defined in the LTE as an example): the signal quality of the neighbour cell is higher than the signal quality of the serving cell by a certain offset, the specific mathematical description of which is Mn+Ofn+Ocn−Hys>Ms+Ofs+Ocs+Off, wherein the parameters comprise RSRP or RSRQ (the serving cell is Ms, and the neighbour cell is Mn) measured by the UE, and also comprise frequency specific offset (wherein the frequency of the serving cell is Ofs and the frequency of the neighbour cell is Ofs), cell specific offset (wherein the frequency of the serving cell is Ocs and the frequency of the neighbour cell is Ocn), Off is offset, Hys is hysteresis.
In order to meet the demands for greater bandwidth, the LTE-A (LTE Advance, advanced long-term evolution) proposes to use the method of carrier aggregation to achieve greater bandwidth, and at this time, the UE can work in multiple continuous or discontinuous carriers (each carrier is referred to as Component Carrier), as shown in FIG. 1. One of the component carriers is a Primary Component Carrier (PCC), and other carriers are Secondary Component Carriers (SCC), wherein in each component carrier, there is a serving cell providing services for the UE, the serving cell on the PCC is a Primary Serving Cell (Pcell), the serving cell on the SCC is a Secondary Serving Cell (Scell). In a single-carrier system, since there is only one serving cell, there is no need to indicate the serving cell in the existing measurement configurations (measurement object, measurement identity, reporting configuration). But for a multi-carrier system, since there may be multiple serving cells, and different measurement assignments will be configured in correspondence with different serving cells, the related art above cannot meet the requirements, namely the existing measurement configurations cannot distinguish between a primary serving cell and a secondary serving cell.